<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>my css</title>
    <style>
        * {   /*通用选择器，匹配所有元素*/
            padding: 0;  /*内边距*/
            margin: 0;   /*外边距*/
        }
        body {
            background-color: silver;
        }
        h1 {
            text-align: center;
            background-color: orangered;
        }
        .c1 {   /*为类设置样式要加上前缀.*/
            color: darkblue;
        }
        /*
        p.c2 {    !*拥有`class="c2"`的p元素*!
            font-weight: bold;
            color: purple;
        }
        */
        p .c2 {    /**p标签内部拥有`class="c2"`的元素**/
            font-weight: bold;
            color: purple;
        }
        #id1 {
            text-align: right;
        }
        .c1, .c2, #id1 {
            text-decoration: underline;
        }
    </style>
</head>
<body>
<h1>达内云计算 Cloud Computing</h1>
<div id="id1">达内云计算 Cloud Computing</div>
<div>达内云计算 Cloud Computing</div>
<div>达内云计算 Cloud Computing</div>
<div>达内云计算 Cloud Computing</div>
<div>达内云计算 Cloud Computing</div>
<p class="c1">达内云计算 Cloud Computing</p>
<p>达内云计算 <span class="c1">Cloud Computing</span></p>
<p>达内云计算 <span class="c1">Cloud Computing</span></p>
<p class="c2">达内云计算 Cloud Computing</p>
<p>达内云计算 <span class="c2">Cloud Computing</span></p>
<div class="c1">达内云计算 Cloud Computing</div>
<div class="c2">达内云计算 Cloud Computing</div>
<div>达内云计算 <span class="c2">Cloud Computing</div>
</body>
</html>